Process for producing maleic anhydride utilizing a catalyst containing a siliceous metal-containing crystalline composition

ABSTRACT

A novel siliceous crystalline composition of matter further comprising one or more metals is prepared by admixing a basic silica salt and a dissolved metal salt in the presence of a quaternary ammonium ion and subsequently heating under pressurized conditions. This novel composition of matter is useful as a catalyst for oxidation, alkylation, disproportionation, synthesis gas conversion, hydrocracking, and hydrodewaxing.

CROSS REFERENCES TO RELATED APPLICATIONS

This application is a division of U.S. patent application Ser. No.335,887, filed in the U.S. Pat. and Trademark Office on Dec. 30, 1981now abn.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to siliceous crystalline compositions, amethod for preparing same, and processes which involve its use. Moreparticularly, the invention relates to siliceous crystallinecompositions further containing a metallic component.

2. Prior Art

Silicon is second only to oxygen as the most prevalent element in theearth's crust (˜28% by weight) and is found in widely diverse minerals.Free silica, for example, occurs in many crystalline forms, with quartzbeing by far the most prevalent form. Additionally, silicon chemicallybonds with oxygen to form silicate minerals, and such minerals form themajor constituents of the earth's outer layers. Silicates are alsoimportant constituents of meteorites and materials of lunar origin.

Among the commercially important silicate materials are the crystallinealuminosilicate zeolites, which occur in such natural forms as analcime,brewsterite, chabazite, clinoptilolite, dachiardite, erionite,faujasite, ferrierite, gismondine, gmelinite, heulandite, laumontile,levynite, mesolite, mordenite, natrolite, offretite, phillipsite,paulingite, scolecite, stilbite, and thomsonite. The commercialusefulness of zeolites encouraged the rapid development of syntheticzeolites, and a great number are now known, the following being amongthose disclosed in the patent literature: Zeolite A (U.S. Pat. No.2,882,243), Zeolite B (U.S. Pat. No. 3,008,803), Zeolite D (CanadianPat. No. 661,981), Zeolite E (U.S. Pat. No. 2,962,355), Zeolite F (U.S.Pat. No. 2,996,358), Zeolite H (U.S. Pat. No. 3,010,789) Zeolite J (U.S.Pat. No. 3,011,869), Zeolite L (U.S. Pat. No. 3,216,789), Zeolite M(U.S. Pat. No. 2,995,423), Zeolite O (U.S. Pat. No. 3,140,252), ZeoliteQ (U.S. Pat. No. 2,991,151) Zeolite R (U.S. Pat. No. 3,030,181), ZeoliteS (U.S. Pat. No. 3,054,657), Zeolite T (U.S. Pat. No. 2,950,952),Zeolite W (U.S. Pat. No. 3,012,853), Zeolite X (U.S. Pat. No.2,882,244), Zeolite Y (U.S. Pat. No. 3,130,007), Zeolite Z (U.S Pat. No.2,972,516), Zeolite ZSM-4 (Canadian Pat. No. 817,915), and Zeolite Beta(U.S. Pat. No. 3,308,069). Other zeolites are also known, as forexample, Zeolite Z-14US disclosed in U.S. Pat. No. 3,293,192, thezeolites disclosed in U.S. Pat. No. 3,227,660, and Zeolite ZSM-2 (U.S.Pat. No. 3,411,874), Zeolite Z-14 (U.S. Pat. No. 3,619,134), Zeolite K-G(U.S. Pat. No. 3,056,654), Zeolite ZK-4 (U.S. Pat. No. 3,314,752),Zeolite ZK-5 (U.S. Pat. No. 3,247,195), Zeolite ZK-21 (U.S. Pat. No.3,355,246), Zeolite UJ (U.S. Pat. No. 3,298,780), and Zeolite W-Z (U.S.Pat. No. 3,649,178).

Both the natural and synthetic zeolites are comprised of a rigidthree-dimensional framework of SiO₄ and AlO₄ tetrahedra joined bycrosslinking oxygen atoms, and the resulting crystal lattice has anelectronegative charge balanced by the inclusion of cations, sodiumbeing almost exclusively found as the cation. The cations haveconsiderable freedom of movement within the crystal framework and may beremoved by ion exchange.

Because of their great affinity for adsorbing water, one of the firstuses of zeolites was for drying or desiccation purposes. But other usessoon developed. In particular, due to their unique crystal structure,wherein each form of zeolite contains pore openings or cavities ofmicroscopic size, many zeolites have been used as molecular sieves, thatis, as agents for separating one molecule from another based upon thesize of a molecule or portion thereof. Additionally, certain zeoliteshave been found to have catalytic properties with respect to hydrocarbonconversion reactions, as for example, in the cracking of hydrocarbons.These catalytic properties depend at least in part upon the zeolitehaving pore openings of sufficient size to allow ingress of relativelylarge hydrocarbon molecules into the interior of the crystal structure.Also critical is the presence of acid sites within the zeolite, whichacid sites are usually produced by replacing some or all of the metalcations within the zeolite with hydrogen ions, using procedures wellknown in the art

One zeolite of enormous importance in the catalysis of hydrocarbonconversion reactions is Zeolite Y, a zeolite having pores of diameterbetween about 6 and 15 angstroms, large enough to permit entry of evenrelatively large aromatic molecules into the zeolite. Zeolite Y, asdisclosed in U.S. Pat. No. 3,130,007, has an X-ray powder diffractionpattern as shown in the following Table I, which reports all lines of atleast weak intensity:

                  TABLE I                                                         ______________________________________                                        Interplanar spacing d (A)                                                                       Relative Intensity                                          ______________________________________                                        14.37-14.15       VS                                                          8.80-8.67         M                                                           7.50-7.39         M                                                           5.71-5.62         S                                                           4.79-4.72         M                                                           4.46-4.33         M                                                           4.29-4.16         W                                                           4.13-4.09         W                                                           3.93-3.88         W                                                           3.79-3.74         S                                                           3.66-3.62         M                                                           3.33-3.28         S                                                           3.04-3.00         M                                                           2.93-2.89         M                                                           2.87-2.83         S                                                           2.78-2.74         M                                                           2.73-2.69         W                                                           2.65-2.61         M                                                           2.39-2.36         M                                                           2.20-2.17         W                                                           2.11-2.08         W                                                           1.76-1.73         W                                                           1.71-1.69         W                                                           ______________________________________                                         Zeolites of the Y type are of especial usefulness in the cracking or     hydrocracking of hydrocarbons, particularly when ion-exchanged to contain     hydrogen ions and when stabilized by either a partial ion exchange with     rare earth cations as disclosed in U.S. Pat. Nos. 3,140,253 and 3,210,267     or by a steam calcination treatment as disclosed in U.S. Pat. No.     4,036,739.

Recently, another crystalline aluminosilicate zeolite, designated ZSM-5,has been established as useful in hydrocarbon conversion catalysis.ZSM-5 is particularly useful in the art of catalytic dewaxing becauseits uniform pore openings of between about 5 and 6 angstroms areespecial suited to admitting waxy paraffinic hydrocarbons whilerejecting larger-sized molecules. ZSM-5 zeolite is more particularlydescribed in U.S. Pat. No. 3,702,886 wherein the following X-ray powderdiffraction pattern is set forth:

                  TABLE II                                                        ______________________________________                                        Interplanar spacing d (A):                                                                      Relative Intensity                                          ______________________________________                                        11.1 ± 0.2     S                                                           10.0 ± 0.2     S                                                            7.4 ± 0.15    W                                                            7.1 ± 0.15    W                                                            7.1 ± 0.15    W                                                           6.3 ± 0.1      W                                                            6.04                                                                                        ± 0.1   W                                                   5.97                                                                          5.56 ± 0.1     W                                                           5.01 ± 0.1     W                                                           4.60 ± 0.08    W                                                           4.25 ± 0.08    W                                                           3.85 ± 0.07    VS                                                          3.71 ± 0.05    S                                                           3.04 ± 0.05    W                                                           2.99 ± 0.02    W                                                           2.94 ± 0.02    W                                                           ______________________________________                                    

The commercial interest in ZSM-5 zeolite led to the development of alarge number of zeolites similar to ZSM-5, which zeolites areexemplified by ZSM-8 (U.S. Pat. No. 3,700,585), ZSM-11 (U.S. Pat. No.3,709,979), ZSM-12 (U.S. Pat. No. 3,832,449), ZSM-20 (U.S. Pat. No.3,972,983), ZSM-23 (U.S. Pat. No. 4,076,842), ZSM-25 (U.S. Pat. No.4,247,416), ZSM-35 (U.S. Pat. No. 4,016,245), ZSM-39 (U.S. Pat. No.4,259,306). Also known are certain ferrierite-type zeolites known asZSM-21 and ZSM-38 (U.S. Pat. No. 4,046,859) as well as other zeolitessuch as ZSM-18 (U.S. Pat. No. 3,950,496) and ZSM-43 (U.S. Pat. No.4,209,497).

In addition to the crystalline aluminosilicate zeolites, certainsiliceous crystalline materials consisting essentially of silicapolymorphs are also useful as molecular sieves. One such silicapolymorph is termed "silicalite" and is described more thoroughly inU.S. Pat. No. 4,061,724 Although similar to ZSM-5 in many respects,silicalite differs in that it is essentially free of aluminum and,unlike the zeolites, is hydrophobic and exhibits essentially no ionexchange properties. Silicalite is further characterized by a crystalstructure comprising a channel system (or pore structure) of straightchannels having an elliptical cross-section, which straight channels areintersected perpendicularly by zigzag channels of nearly circularcross-section. (See "Silicalite, a New Hydrophobic Crystalline SilicaMolecular Sieve" by Flanigen et al., published in Nature, Volume 271,pp. 512 to 516, Feb. 9, 1978.) As reported in U.S. Pat. No. 4,061,724,the X-ray powder diffraction pattern of silicalite shows the followinglines having a relative intensity of at least 10 percent of theintensity of the strongest line:

                  TABLE III                                                       ______________________________________                                        Interplanar     Relative                                                      Spacing         Intensity                                                     d (Angstroms)   I/I.sub.o                                                     ______________________________________                                        11.1            100                                                           10.02           64                                                            9.73            16                                                            5.98            14                                                            3.85            59                                                            3.82            32                                                            3.74            24                                                            3.71            27                                                            3.64            12                                                            3.34            11                                                            2.98            10                                                            ______________________________________                                    

Besides zeolites and silica polymorphs, other siliceous crystallinematerials are known in the art, and these include the syntheticorganosilicates disclosed in U.S. Pat. No. 4,104,294, the silicatesdisclosed in U.S. Pat. No. 4,208,305, and the metal organosilicatesdisclosed in U.S. Pat. No. Re. 29,948. In view of these patents, and thenumerous patents relating to zeolites, and the published literaturerelating to silicalite (and similar materials such as "Silicalite-2," acomposition disclosed in an article entitled "Silicalite-2, a SilicaAnalogue of the Aluminosilicate Zeolite ZSM-11," published in Nature byBibby et al., Volume 280, pages 664 and 665, Aug. 23, 1979), it isevident that there is an ongoing effort in the art to develop new anduseful siliceous crystalline materials, especially those having auniform pore structure.

The main object of the invention is to provide a metal-containingsiliceous crystalline material useful in catalysis, as for example inthe hydrodewaxing of paraffinic hydrocarbons. Another object is toprovide a method for synthesizing metal-containing siliceous crystallinematerials, and especially rare earth, siliceous crystalline materials.Yet another object is to provide a catalytic process wherein thecrystalline composition of the invention is utilized as a catalyst orcomponent thereof. These and other objects and advantages will revealthemselves to those skilled in the art in light of the followingdescription of the invention

SUMMARY OF THE INVENTION

In accordance with the present invention, a siliceous metal-containingcrystalline composition is prepared by admixing a basic solution of asilica salt and a metal component, followed by addition of a quaternaryammonium compound having a formula of R₄ N⁺ X⁻ wherein R is an organicsubstituent containing from one to fifty carbon atoms and X is either ahydroxide or a halide. After hydrothermal aging under pressure, thereaction mixture containing the quaternary ammonium compound yields ametal-containing, siliceous crystalline composition useful as a catalystfor oxidation, alkylation, disproportionation, synthesis gas conversion,hydrocracking, and most especially, hydrodewaxing.

The crystalline composition of the invention is characterized by anX-ray powder diffraction pattern having its strongest absorption line atan interplanar spacing less than 5 Å, and most usually at about 3.85±0.4Å. In addition, the X-ray powder diffraction pettern exhibits asignificant absorption line of at least weak intensity at one or more ofthe following interplanar spacings: 11.0±0.2 Å, 9.96±0.2 Å, 3.75±0.2 Å,3.71±0.2 Å, 3.71±0.2 Å, 3.64±0.2 Å, 3.44±0.2 Å, 3.30±0.2 Å, 3.14±0.2 Å,3.05±0.2 Å, or 2.97±0.2 Å, and usually the diffraction pattern indicatesonly one significant line between the interplanar spacings of 3.8 and3.9 Å.

The X-ray powder diffraction pattern is most usually characterized bylines having an intensity relative to the strongest line as shown in thefollowing Table IV:

                  TABLE IV                                                        ______________________________________                                        Interplanar     Relative                                                      Spacing         Intensity                                                     d (Angstroms)   I/I.sub.o                                                     ______________________________________                                        11.0 ± 0.2   W to M                                                        9.96 ± 0.2   W to M                                                        3.85 ± 0.4   S to VS                                                       3.75 ± 0.2   W to M                                                        3.71 ± 0.2   M                                                             3.64 ± 0.2   M                                                             3.44 ± 0.2   M to VS                                                       3.30 ± 0.2   W to S                                                        3.14 ± 0.2   W to S                                                        3.05 ± 0.2   W                                                             2.97 ± 0.2   W                                                             ______________________________________                                    

with it being understood, in the foregoing table and others presentedhereinafter with respect to X-ray powder diffraction patterns, that Wrefers to a line of weak intensity from 10% up to 25% of that of thestrongest line in the X-ray diffraction pattern, M refers to a line ofmedium intensity from 25% up to 60% of the strongest line, S refers to aline of strong intensity from 60% up to 80% of the strongest line, andVS refers to a line of very strong intensity from 80% up to including100% of that of the strongest line. Thus, if as is customary in theinterpretation of X-ray diffraction data, an arbitrary value of 100 isassigned to the strongest line, then the weak lines herein will havevalues from 10 up to 25, the medium from 25 up to and 60, the strongfrom 60 up to 80, and the very strong from 80 up to and including 100.Also, as reported in the foregoing table, certain lines are reported inranges, as for example, from W to M in the case of the interplar spacingat 11.0 Å, so that the values for this interplanar spacing span the weakand medium ranges, i.e., from a minimum value of 10 up to but notincluding 60.

DETAILED DESCRIPTION OF THE INVENTION

The crystalline compositions of the present invention may be prepared byreacting a quaternary ammonium ion and a gel formed by combining a metalcomponent under alkaline conditions with a source of silicon, such as anaqueous liquid containing a silicon component in dissolved or colloidalform. The silicon source is usually contained in an alkaline, aqueousmedium and may, for example, be an alkaline solution of a silicate salt,with salts of ammonia and the alkali metals generally proving to be themore suitable. A preferred solution is a sodium silicate solutioncontaining between about 25 and 40 weight percent SiO₂ and, optionally,may further contain a surfactant such as Dowfax 2Al marketed by the DowChemical Company. Alternatively and more preferably, a reactive silicasol may be utilized, such as a commercial Ludox containing 30 percent byweight SiO₂ in an alkaline medium. Other sources of silica includecolloidal silicas in aqueous basic media, as well as silica gels andfume silicas in reactive forms.

To the alkaline solution containing a source of silica is added acomponent containing the metal or metals desired in the finalcrystalline product. This may be accomplished, for example, by thedirect addition of a solid metal salt if it is soluble in the aqueous,alkaline medium containing the silica component. Many metals, however,and especially the rare earth metals, are not soluble in alkaline media,and as a result, it is generally necessary to prepare an aqueous acidicsolution containing the metal desired in the final product. Suchsolutions usually contain a dissolved chloride, nitrate, acetate,carbonate, or oxalate of the desired metal and further contain thedesired metal in any concentration up to the solubility limit, withconcentrations of 0.5% to 10% by weight being preferred.

The metals which may be utilized to produce the metal-containingsiliceous compositions of the invention include all metals, semi-metals,and metalloids, and it will be understood that reference to a "metal" or"metals" herein is meant to include the semi-metals and metalloids, aswell as those elements which are truly metallic. In general, the moresuitable metals are selected from the group consisting of titanium,chromium, vanadium, iron, cobalt, nickel, copper, antimony, manganese,niobium, molybdenum, germanium, ruthenium, arsenic, tellurium, tantalum,tungsten, rhenium, osmium, and iridium. Preferred metals includeyttrium, zirconium, scandium, zinc, rhodium, palladium, silver, cadmium,indium, tin, hafnium, platinum, gold, mercury, thallium, lead, bismuth,actinium, thorium, and uranium, with the most preferred metals being themembers of the lanthanide series: lanthanum, cerium, praseodymium,neodymium, promethium, samarium, europium, gadolinium, terbium,dysprosium, holmium, erbium, thulium, ytterbium, and lutetium.

Metals which are generally unsuitable in the invention include thealkali metals and the alkaline earth metals, since their use tends toresult in the production of a crystalline product containing a metalremovable by dissolution in water. Also unsuitable are aluminum, boron,and gallium, which, although resulting in a stable composition, usuallyresult in either a zeolite (if aluminum is utilized) or a zeolite-likeproduct (if boron or gallium is chosen). The compositions of theinvention herein will differ from the zeolites in having little or noion exchange properties and will usually be hydrophobic as well,adsorbing less than about 10%, preferably less than about 5%, of theirweight in water at 25° C. in the presence of water vapor at a partialpressure of about 0.2 to 1.0 p.s.i.a. Accordingly, it is most highlypreferred in the invention that the reactants utilized in preparing thecompositions herein be essentially free of aluminum, boron, and gallium,containing such metals in trace proportions no greater than about 0.1%by weight, so that the final crystalline composition is essentially freeof aluminum, boron, and gallium, containing said metals in a totalproportion no greater than about 0.75% by weight (calculated as theoxides thereof), with proportions less than 0.5% by weight being mostpreferred.

In accordance with the invention, one or more of the foregoing metals orcompounds thereof are added to the solution containing the siliconsource, and under alkaline conditions, and preferably under highlyalkaline conditions wherein a pH above about 10 is maintained, agelatinous substance is produced. The alkaline conditions necessary forreaction are usually maintained by utilizing a silica source ofsufficiently high pH to ensure that, even with the addition of a metaldissolved in an acid medium, the pH of the reaction mixture will stillnot fall below 7.0, and will preferably remain above 10.0. If necessary,however, pH adjusters, such as ammonium hydroxide or pyridine, may beadded to maintain the pH at the desired level.

Since the gel formed by the reaction of the metal component and thesilicon source is a precursor of the final crystalline productcomposition, and since it is usually desirable, although not critical,that the product composition contain the metal or metals in a uniformdistribution, it is highly preferable that the reaction between thesilicon and metal components be performed under controlled conditionsproducing a gel containing the metal or metals in a fairly homogeneousdistribution. This may be accomplished by simultaneously adding thealkaline solution containing the silicon component and a solution of thedesired metal to a reaction vessel at constant rates, thereby ensuring arelatively constant reaction rate of metal with silicon component,producing a homogeneous product having a metal content dependent uponthe rate of metal addition to that of silicon.

After the metal and silicon-containing gel has been produced inaccordance with the above procedure or its equivalent, the gel isreacted with a quaternary ammonium ion, provided from a source such asan aqueous solution of a quaternary ammonium component selected from thegroup consisting of the n-propylammonium and n-butylammonium bromidesand chlorides. The preferred compound is tetrapropylammonium bromide,but any of a number of compounds of formula R₄ N⁺ X⁻ wherein X is eithera hydroxide or a halide and R is an organic moiety containing from 1 to50 carbon atoms may be utilized. Of these, the more suitable will havean R moiety consisting of an alkyl group containing from 1 to 6 carbonatoms.

The quaternary ammonium compound selected for reaction may be addeddirectly to the mixture in which the gel was produced or, lesspreferably, generated in situ by addition of appropriate chemicalreactants, as for example, tripropyl amine plus n-propyl bromidedissolved in an organic solvent such as methyl ethyl ketone. Usually,however, in situ generation will be found less convenient than directaddition of a quaternary ammonium compound. Further, since the reactionof tripropyl amine and n-propyl bromide, or other quaternary ammoniumion precursors, cannot be expected to proceed to completion, greatercosts will be incurred with in situ generation than with directaddition, since larger quantities of chemicals will usually be requiredto ensure an adequate amount of available quaternary ammonium ions.

To produce the crystalline product of the invention, the admixture ofquaternary ammonium compound and the gel, which admixture will generallybe in the form of an amorphous slurry, is subjected to pressurizedhydrothermal aging conditions This may be accomplished by subjecting theslurry to temperatures in the range of 25° to 300° C. and pressuresranging from 15 to 2,000 p.s.i.g., with temperatures of 120° to 200° C.and pressures of 25 to 2000 p.s.i.g. being preferred. A crystallinematerial will then form, usually after a time period of between about 1and 500 hours; the exact time period will vary considerably, as moresevere conditions of temperature and pressure will tend to yield thecrystalline material more rapidly than will relatively mild conditions.

The crystalline material is then separated from the mother liquor, andafter washing in water to remove water-soluble components, anorgano-metallic, silicon-containing crystalline product is recovered.If, as most usually is the case, a crystalline product free of organiccomponents is desired, then the organo-crystalline substance issubjected to a high temperature calcination, generally in the presenceof air, so as to remove virtually all the organo-componcnt and leave aproduct composition of the invention.

Although the invention is not limited to any theory of operation, it isbelieved that siliceous, metal-containing crystalline compositionsprepared by the foregoing method or its equivalent have a crystalframework, depending upon the metal or metals introduced into thecomposition, composed of either silicon or oxygen atoms or silicon,oxygen, and metal atoms. In the former instance, the composition isbelieved most properly termed a metal-containing crystalline silica,with one or more metal oxides being contained in the voids orinterstices formed by the silicon-oxygen framework. Such a structure isespecially believed to result when the metal introduced into thecrystalline composition is in an oxidation state wherein the ionicradius thereof is above about 0.75 Å. On the other hand, for metalsintroduced in a cationic form of ionic radius smaller than 0.75 Å, it isbelieved that, at least to some extent, the metals form part of thecrystal framework, with the resultant composition being a metalsilicate, or perhaps a metal silicate in combination with a crystallinesilica or metal-containing crystalline silica. The preferredcompositions are those comprising a metal-containing crystalline silica,especially these containing a metal in an oxidation state wherein theionic radius is above about 0.9 Å.

The crystalline compositions of the invention usually contain betweenabout 1 and 25 percent by weight of the desired metal or metals,calculated as the most common oxide or oxides thereof. Preferredcompositions contain between 3 and 20 percent by weight of the metals,and the atom ratio of metal to silicon for the preferred compositionsfall in the range of 0.03 to 0.15. A somewhat broader range pertains tosuitable compositions, i.e., from 0.01 to 0.20.

The X-ray powder diffraction patterns of the crystalline compositionsherein vary according to the amount and kind of metal or metalsintroduced into the composition, as well as by the degree of homogenietyachieved in the preparation of the gel precursor described hereinbefore.Typical compositions are characterized by an X-ray powder diffractionpattern having its strongest line at an interplanar spacing less than 5Å, usually at between 3 and 4 Å, and most usually and preferably at3.85±0.4 Å, with significant lines of at least weak intensity appearingat one or more of the following interplanar spacings: 11.0±0.2 Å,9.96±0.2 Å, 3.75±0.2 Å, 3.71±0.2 Å, 3.64±0.2 Å, 3.44±0.2 Å, 3.30±0.2 Å,3.14±0.2 Å, 3.05±0.2 Å, or 2.97±0.2 Å.

The preferred crystalline compositions are characterized by thefollowing X-ray powder diffraction pattern:

                  TABLE V                                                         ______________________________________                                        Interplanar     Relative                                                      Spacing         Intensity                                                     d (Angstroms)   I/I.sub.o                                                     ______________________________________                                        11.0 ± 0.2   M                                                             9.96 ± 0.2   M                                                             3.85 ± 0.4   VS                                                            3.75 ± 0.2   M                                                             3.71 ± 0.2   M                                                             3.64 ± 0.2   M                                                             3.44 ± 0.2   M to VS                                                       3.30 ± 0.2   W to S                                                        3.14 ± 0.2   W to S                                                        3.05 ± 0.2   W                                                             2.97 ± 0.2   W                                                             ______________________________________                                    

A comparison of the above X-ray diffraction pattern with other siliceouscrystalline compositions reveals significant differences. For example,in comparison to silicalite, the above diffraction pattern indicatesonly one significant line between the 3.8 and 3.9 Å interplanar spacingswhereas silicalite is characterized by a doublet between these spacings,with one significant line usually being at 3.82 Å and the other at 3.85Å. Another difference between the present compositions and silicalite isfound in the fact that silicalite has its strongest line at about 11.1Å0 whereas the crystalline compositions of the invention all have theirstrongest lines below an interplanar spacing of 5 Å, with the strongestline usually being at 3.85Å±0.4, and occasionally at 3.44±0.2.

Substantial differences may also be found between the crystallinecomposition of the invention and other crystalline materials of theprior art, such as the zeolites. In comparison to the zeolites, thepresent compositions are not only essentially aluminum-free, but themetals contained in the crystalline compositions of the invention aresubstantially non-ionexchangeable, as for example in aqueous liquidmedia. Also, numerous differences based upon X-ray diffraction patternsbetween the siliceous crystalline materials of the invention and thezeolites may be found. In one illustration, the present compositions arefound to be significantly different from metal-exchanged ZSM-5compositions, and this is evidenced by the fact that the significantlines at interplanar spacings of 3.14±0.2 Å, 3.30±0.2 Å, 3.44±0.2 Å, and3.64±0.2 Å are found in the X-ray diffraction pattern of manyembodiments of the composition of the invention, but ZSM-5 is notreported to have an X-ray diffraction pattern showing significant linesat these locations. Moreover, ZSM-5 zeolites have significant lines notfound to pertain to the composition of the invention, with the strongline at 10.0±0.2 Å for ZSM-5 being illustrative.

The following Examples provide methods for producing various embodimentsof the composition of the present invention, and X-ray diffraction datawith respect to several of these embodiments are also provided. TheExamples, however, are not to be construed as limiting the scope of theinvention, which is defined by the claims.

EXAMPLE 1

A metal-containing siliceous crystalline composition is synthesized fromNa₂ SiO₃, Dowfax 2Al, acetic acid, sodium chloride, lanthanum nitrateand water. A silica-containing reaction solution is prepared bydissolving 3380 g Na₂ SiO₃ and 10 g Dowfax 2Al in 1960 ml water. Oneliter of the silica-containing solution is added to a buret.

A second reaction solution containing lanthanum in the form of adissolved metal salt is prepared by adding 125 ml acetic acid, 38 gsodium chloride, and 44 g lanthanum nitrate to 510 ml H₂ O. One-halfliter of the metallic salt-containing solution is added to a secondburet. Each buret is equipped with a liquid flow rotamer for controllingthe rate at which the solution is added.

A cogel is formed by adding simultaneously the basic silica solution andthe metallic solution to a three-neck flask. By use of the controlledflow burets the silica-containing solution is added at twice the rate ofthe metallic-containing solution. The reaction mixture is rapidlystirred throughout the addition, by use of an overhead stirrer.

After the liquid contents of the burets are added to the reaction flask,a mixture of 54 g tri-propylamine, 49 g n-propyl bromide and 94 gmethylethylketone is added. This reaction mixture is stirred andrefluxed for 16 hours.

The resulting slurry is placed in a two-liter autoclave purged with anitrogen atmosphere and then subjected to a pressure of 100 p.s.i.g. andheated to 320° F. for 24 hours. While in the autoclave, the reactionmixture is continuously stirred. The resulting crystalline material iswashed with one liter of water and calined at 250° C. An X-ray powderdiffraction pattern of the resulting lanthanum-containing crystallinecomposition is presented in the following Table VI

                  TABLE VI                                                        ______________________________________                                        Interplanar     Relative                                                      Spacing         Intensity                                                     d (Angstrom)    I/I.sub.o                                                     ______________________________________                                        11.0            44                                                            9.96            28                                                            9.83            14                                                            7.41            9                                                             7.05            6                                                             6.68            6                                                             6.50            11                                                            6.08            7                                                             5.97            8                                                             5.71            8                                                             5.56            11                                                            5.13            7                                                             4.98            6                                                             4.60            10                                                            4.35            11                                                            4.25            13                                                            4.08            4                                                             3.99            10                                                            3.85            100                                                           3.75            32                                                            3.71            44                                                            3.64            44                                                            3.56            6                                                             3.44            29                                                            3.30            20                                                            3.14            15                                                            3.05            11                                                            2.97            12                                                            2.94            6                                                             ______________________________________                                    

EXAMPLE 2

The procedure of Example 1 is repeated except that 33 g of ceriumnitrate is added in place of 44 g of lanthanum nitrate. An X-ray powderdiffraction pattern of the resulting cerium-containing crystallinecomposition is presented in the following Table VII:

                  TABLE VII                                                       ______________________________________                                        Interplanar     Relative                                                      Spacing         Intensity                                                     d (Angstrom)    I/I.sub.o                                                     ______________________________________                                        11.0            45                                                            9.96            26                                                            9.83            19                                                            7.41            9                                                             6.68            5                                                             6.50            7                                                             6.08            9                                                             5.71            7                                                             5.56            12                                                            5.13            9                                                             4.98            6                                                             4.60            7                                                             4.35            9                                                             4.25            14                                                            4.08            9                                                             3.99            9                                                             3.85            100                                                           3.75            26                                                            3.71            50                                                            3.64            43                                                            3.44            67                                                            3.30            48                                                            3.14            50                                                            3.05            12                                                            2.97            16                                                            2.94            5                                                             ______________________________________                                    

EXAMPLE 3

The procedure of Example 1 is repeated except that 37 g of Pr(C₂ H₃ O₂)₃is added in place of 44 g of lanthanum nitrate. An X-ray powderdiffraction pattern of the resulting crystalline product is presented inthe following Table VIII:

                  TABLE VIII                                                      ______________________________________                                        Interplanar     Relative                                                      Spacing         Intensity                                                     d (Angstrom)    I/I.sub.o                                                     ______________________________________                                        11.0            38                                                            9.96            29                                                            6.50            12                                                            6.08            6                                                             5.97            12                                                            5.13            15                                                            4.98            6                                                             4.60            9                                                             4.35            9                                                             4.25            9                                                             3.85            100                                                           3.75            32                                                            3.71            34                                                            3.64            38                                                            3.44            85                                                            3.30            65                                                            3.14            66                                                            3.05            12                                                            2.97            15                                                            ______________________________________                                    

EXAMPLE 4

The procedure of Example 1 is repeated except that 48 g of Sn(C₂ H₃ O₂)₂is added in place of 44 g of lanthanum nitrate. An X-ray powderdiffraction pattern of the resulting tin-containing crystallinecomposition is as shown in the following Table IX:

                  TABLE IX                                                        ______________________________________                                        Interplanar     Relative                                                      Spacing         Intensity                                                     d (Angstrom)    I/I.sub.o                                                     ______________________________________                                        11.0            51                                                            9.96            31                                                            9.83            14                                                            7.41            10                                                            6.50            13                                                            6.08            10                                                            5.56            10                                                            5.13            10                                                            4.60            13                                                            4.35            10                                                            4.25            13                                                            3.85            100                                                           3.75            39                                                            3.71            49                                                            3.64            42                                                            3.44            79                                                            3.30            52                                                            3.14            58                                                            3.05            13                                                            2.97            13                                                            ______________________________________                                    

EXAMPLE 5

The procedure of Example 1 is repeated except that 106 g oftetrapropylammonium bromide is added in place of 54 g of tri-propylamineand 49 g n-propyl bromide.

EXAMPLE 6

The procedure of Example 1 is repeated except that 22 g La(NO₃)₃ 0.6H₂ Oand 24 g Sn(C₂ H₃ O₂)₂ are added in place of 44 g of lanthanum nitrate.An X-ray powder diffraction pattern of the resulting crystalline productis as shown in the following Table X:

                  TABLE X                                                         ______________________________________                                        Interplanar     Relative                                                      Spacing         Intensity                                                     d (Angstrom)    I/I.sub.o                                                     ______________________________________                                        11.0            21                                                            9.96            15                                                            6.50            9                                                             5.56            8                                                             5.13            18                                                            4.60            8                                                             4.35            8                                                             4.25            10                                                            3.99            8                                                             3.85            64                                                            3.75            18                                                            3.71            37                                                            3.64            36                                                            3.56            24                                                            3.44            100                                                           3.30            58                                                            3.14            77                                                            3.05            10                                                            2.97            10                                                            ______________________________________                                    

The siliceous, metal-containing crystalline material of the inventionfinds usefulness as a molecular sieve, but is most especially useful asa catalyst or a catalyst component In general, one selects a metal forthe crystalline composition of the invention which catalyticallypromotes the desired chemical reaction. For example, in the oxidation ofH₂ S to elemental sulfur (using O₂ or SO₂ as oxidant) or sulfur dioxide(using O₂ oxidant) at temperatures between about 250° and 900° F., andpressures between about 5 and 500 p.s.i.a., and at space velocitiesbetween about 500 and 5,000 v/v/hr., a most suitable choice forcatalytically active metal is vanadium. On the other hand, a Group VIIImetal such as nickel would be a preferred choice with respect toalkylation, transalkylation, or disproportionation reactions. As anillustration, in the alkylation of benzene with propylene toisopropylbenzene, a nickel-containing siliceous crystalline compositionof the invention may be utilized at 300° to 400° F., 250 to 700p.s.i.g., and 1 to 10 WHSV, with the following specific conditions beingmost useful: 325° F., 500 p.s.i.a., and 7.5 weight hourly spacevelocity. Another catalytic use for the crystalline compositions hereinis in synthesis gas conversion wherein hydrogen is mixed with carbonmonoxide, as for example in molar ratios between 2:1 and 3:1, H₂ :CO,with the resultant mixture then being converted to a distribution ofFischer-Tropsch products such as methane, ethane, ethylene, and aromaticcompounds by passage over a catalyst containing a siliceous crystallinecomposition of the invention further containing iron, nickel, or cobalt.For this purpose, temperatures between 480° and 750° F., pressuresbetween 250 and 2,000 p.s.i.g., and space velocities between 1,500 and10,000 GHSV are suitable, with the following conditions being consideredmost useful: 662° F., 1,000 p.s.i.g., and 4,000 GHSV. Similar conditionsare useful for converting water and carbon monoxide to methanol withnickel, cobalt, or iron-containing crystalline compositions of theinvention.

One especially preferred catalytic use for the compositions of theinvention is in catalytic hydrodewaxing. Oftentimes in hydrodewaxing,the object is to lower the pour point, freeze point, or viscosity of aliquid hydrocarbon by contact with a hydrodewaxing catalyst in thepresence of hydrogen under appropriate conditions of elevatedtemperature and pressure, wherein the waxy paraffins of the liquidhydrocarbon are converted, by a hydrocracking mechanism, and in manycases a highly selective mechanism for hydrocracking the paraffins overother components, to product hydrocarbons of lower average molecularweight and boiling point. In the present invention, this process ismodified by utilizing a hydrodewaxing catalyst containing a crystallinecomposition of the invention, with crystalline compositions containing aGroup VIB metal or a Group VIII metal being preferred, and with a GroupVIB metal and VIII metal in combination being highly preferred, and withnickel and tungsten in combination being most highly preferred.Conditions for operation may be those conventionally utilized inhydrodewaxing, as for example, temperatures above 650° F., pressuresabove 750 p.s.i.g., a space velocity between 0.1 and 10 LHSV, and ahydrogen recycle rate greater than 500 standard cubic feet per barrel offeed. Preferred conditions are as follows: 720° to 750° F. operatingtemperature, 2,000 to 2,500 p.s.i.g operating pressure, a space velocityof 0.5 to 2.0 LHSV, and a hydrogen recycle rate of 6,000 to 10,000scf/bbl.

When used as a catalytic agent in one or more of the foregoingprocesses, the siliceous, metal-containing crystalline compositions ofthe invention are usually dispersed in a porous refractory oxide, suchas alumina, silica, silica-alumina, etc. This may be accomplished, forexample, by first admixing the crystalline composition with an alumina,silica, or silica-alumina gel, then shaping the admixed material into adesired size and shape, e.g., by extrusion through a die havingsmall-diameter (e.g., 1/16 to 1/4 inch) circular holes followed bycutting into particles of suitable length (e.g., 1/16 to 1/2 inch), andfinally calcining the shaped material in the presence of air at anelevated temperature, as for example, 900° to 1600° F. If desired, oneor more active catalytic metals (in addition to those present in thecrystalline composition) may be introduced into the catalyst by any of avariety of methods. In one embodiment, the shaped material prior tocalcination is impregnated with a liquid containing the active metal indissolved form. In another, the refractory oxide gel is admixed with asolid salt or hydroxide of the desired active metal, the resultingadmixture then being shaped and calcined as described above.

Additionally, the foregoing catalysts are believed to be substantiallyimproved by the presence of a rare earth metal component in thecrystalline composition of the invention The rare earth metal eitherpromotes or aids in promoting the desired chemical reactions and isfurther believed to increase the stability of the crystalline materialat elevated temperatures (e.g., above 900° F.), particularly in thepresence of water vapor, as for example at temperatures of 1100° to1600° F. in the presence of water vapor at a partial pressure aboveabout 5 p.s.i.a. Thus, it is a preferred embodiment of the inventionthat catalysts prepared with the crystalline composition of theinvention contain a rare earth metal component, either alone if activefor promoting the intended chemical conversion or, if not, inconjunction with another metal component having the required catalyticactivity.

Catalytic crystalline compositions of the invention containing alanthanide element therein are highly useful for catalytically promotingthe conversion of C₄ to C₁₀ hydrocarbons to maleic anhydride byoxidation. In this process, a cerium-containing crystalline compositionis preferred, and such a composition may be incorporated into a suitablecatalyst by comulling with a solution or slurry containing vanadium,tin, and phosphorus components followed first by shaping into a desiredsize and shape and then calcining. A most preferred comulling procedureinvolves admixing a slurry comprising ammonium metavanadate, phosphoricacid, stannous chloride, water, ethanol, and hydrochloric acid with acerium-containing crystalline composition and a porous refractory oxideprecursor, such as an alumina or silica-alumina gel. After shaping andcalcining operations, an active catalyst is produced for promoting theoxidation of hydrocarbons such as butane, butene and butadiene with air(or other source of oxygen) to maleic anhydride under conditionsselected from the following: 500° to 1200° F., 500 to 3,000 GHSV, and 5to 50 p.s.i.a.

Although the invention has been described by reference to severalembodiments, including a preferred embodiment thereof, together withexamples relating to preparation methods suitable for producing thecompositions of the invention, it is not intended that the invention belimited to the disclosed embodiments or examples. Obviously, manyvariations, modifications, combinations and alternatives of theinvention as described will be apparent to those skilled in the art.Accordingly, the invention is intended to embrace all such variations,modifications, alternatives, and combinations which fall within thespirit and scope of the appended claims.

I claim:
 1. A process for producing maleic anhydride from a C₄ to C₁₀hydrocarbon which comprises oxidizing said hydrocarbon in the presenceof an oxidation catalyst containgin vanadium, tin, phosphorus and acrystalline composition comprising silicon, oxygen and a rare earthmetal selected from the group consisting of lanthanum, cerium,praseodymium, neodymium, promethium, samarium, europium, gadolinium,terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium andmixtures thereof, wherein said crystalline composition contains lessthan about 0.75 weight percent of aluminum, boron and gallium and ischaracterized by a X-ray powder diffraction pattern having a line of atleast strong intensity at an interplanar spacing less than about 5Angstroms and lines of at least weak intensity at interplanar spacingsof 3.64 Angstroms, 3.44 Angstroms, 3.30 Angstroms and 3.14 Angstroms. 2.A process as defined by claim 1 wherein said C₄ to C₁₀ hydrocarbon isselected from the group consisting of butane, butene and butadiene.
 3. Aprocess as defined by claim 1 wherein said C₄ to C₁₀ hydrocarbon isoxidized by contacting said hydrocarbon with air under oxidationconditions.
 4. A process as defined by claim 1 wherein said rare earthmetal comprises cerium.
 5. A process as defined by claim 1 wherein saidlines at interplanar spacings of 3.64 Angstroms, 3.44 Angstroms, 3.30Angstroms and 3.14 Angstroms are of at least medium intensity.
 6. Aprocess as defined by claim 1 wherein said line of at least strongintensity occurs at an interplanar spcaing between about 3.8 and 3.9Angstroms and wherein said X-ray powder diffraction pattern does notcontain any other significant line at an interplanar spacing between 3.8and 3.9 Angstroms.
 7. A process as defined by claim 1 wherein saidcrystalline composition is essentially free of aluminum, boron andgallium.
 8. A process as defined by claim 6 wherein said X-ray powderdiffraction pattern also contains a line of at least medium intensity atinterplanar spacings of 3.71 Angstroms and 3.75 Angstroms.
 9. A processas defined by claim 8 wherein said X-ray powder diffraction pattern alsocontains a line of at least weak intensity at an interplanar spacing of2.97 Angstroms.
 10. A process as defined by claim 6 wherein said X-raypowder diffraction pattern also contains lines of at least mediumintensity at interplanar spacings of 11.0±0.2 Angstroms, 9.96±0.2Angstroms, 3.75 Angstroms and 3.71 Angstroms.
 11. A process as definedby claim 10 wherein said line at an interplanar spacing between about3.8 and about 3.9 Angstroms occurs at an interplanar spacing of 3.85Angstroms and is the strongest line in said X-ray powder diffractionpattern.
 12. A process as defined by claim 1 wherein said crystallinecomposition is characterized by an X-ray powder diffraction patterncomprising the interplanar spacings and relative intensities set forthin Table IV.
 13. A process for producing maleic anhydride from a C₄ toC₁₀ hydrocarbon which comprises oxidizing said hydrocarbon in thepresence of an oxidation catalyst containing vanadium, tin, phosphorusand a crystalline composition which comprises silicon, oxygen and a rareearth metal selected from the group consisting of lanthanum, cerium,praseodymium, neodymium, promethium, samarium, europium, gadolinium,terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium andmixtures thereof, wherein said crystalline composition is substantiallyfree of aluminum, boron and gallium and is characterized by an X-raypowder diffraction pattern having a line of at least strong intensity atan interplanar spacing between about 3.8 and about 3.9 Angstroms andlines of at least weak intensity at interplanar spacings of 3.64±0.01Angstroms, 3.44±0.01 Angstroms, 3.30±0.01 Angstroms and 3.14±0.01Angstroms.
 14. A process as defined by claim 13 wherein said rare earthmetal is selected from the group consisting of lanthanum, cerium andpraseodymium.
 15. A process as defined by claim 13 wherein said lines atinterplanar spacings of 3.64 Angstroms, 3.44 Angstroms, 3.30 Angstromsand 3.14 Angstroms are of at least medium intensity.
 16. A process asdefined by claim 15 wherein said line at an interplanar spacing betweenabout 3.8 and about 3.9 Angstroms is the strongest line in said X-raypowder diffraction pattern.
 17. A process for producing maleic anhydridefrom a C₄ to C₁₀ hydrocarbon which comprises oxidizing said hydrocarbonin the presence of an oxidation catalyst containing vanadium, tin,phosphorus and a crystalline composition which comprises silicon, oxygenand a rare earth metal contained substantially in a form not removableby cation exchange in an aqueous liquid medium, said rare earth metalbeing selected from the group consiting of lanthanum, cerium,praseodymium, neodymium, promethium, samarium, europium, gadolinium,terbiam, dysprosium, holmium, erbium, thulium, ytterbium, lutetium andmixtures thereof, and wherein said crystalline composition isessentially free of aluminum, boron and gallium and is characterized byan X-ray powder diffraction pattern comprising the interplanar spacingsand relative intensities set forth in Table IV.
 18. A process as definedby claim 17 wherein said lines in Table IV that occur at interplanarspacings of 3.64±0.2, 3.44±0.2, 3.30±0.2, and 3.14±0.2 occur atinterplanar spacings of 3.64 Angstroms, 3.44 Angstroms, 3.30 Angstromsand 3.14 Angstroms and are of at least medium intensity.
 19. A processas defined by claim 18 wherein the line in Table IV which occurs at aninterplanar spacing of 3.85±0.4 is the strongest line in said X-raypowder diffraction pattern.